Allergic disorders and risk of depression: A systematic review and meta-analysis of 51 large-scale studies.

BACKGROUND: Previous studies have suggested that allergic disorders are associated with an increased risk of depression. However, the results are conflicting.

OBJECTIVE: To determine the association between allergic disorders and depression based on large-scale studies.

METHODS: We reviewed relevant articles obtained from PubMed and Embase. Studies were eligible if they reported an association between allergic disorders and depression and provided available data. Study selection, data extraction, and analyses were undertaken. Pooled relative risks (RRs) with 95% confidence intervals (CIs) were calculated.

RESULTS: Of 1,827 studies identified, 51 including more than 2.5 million participants met our inclusion criteria. Overall, the results showed that allergic disorders were associated with a significant increased risk of depression (pooled RR 1.59, 95% CI 1.48-1.71). A higher risk of depression also was observed in patients with asthma (RR 1.59, 95% CI 1.46-1.74) and those with allergic rhinitis (RR 1.57, 95% CI 1.27-1.93). Subgroup analyses were conducted based on sex and age. Children (RR 1.66, 95% CI 1.41-1.96) and adults (RR 1.58, 95% CI 1.44-1.74) with allergic disorders had a higher risk of depression than controls. However, no significant association was found between allergic disorders and risk of depression in male subjects (RR 1.37, 95% CI 0.98-1.91), but a positive association was detected in female subjects (RR 1.65, 95% CI 1.44-1.89).

CONCLUSION: The results from our study showed that allergic disorders significantly increased the risk of depression.